public static PermissionsResolver factory(Server server, Configuration config){
		File groups = new File("perms_groups.txt");
		File users  = new File("perms_users.txt");

		if(!groups.exists() || !users.exists()){
			return null;
		}

		return new FlatFilePermissionsResolver(groups, users);
	}

	public FlatFilePermissionsResolver(){
		this(new File("perms_groups.txt"), new File("perms_users.txt"));
	}

    public FlatFilePermissionsResolver(File groupFile, File userFile) {
		this.groupFile = groupFile;
		this.userFile = userFile;
	}